Cold Trap Expansion Panel for Vacuum Conductance
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Solution Overview
Problem
In-line type cold traps used in vacuum systems face a trade-off between increasing pumping speed and maintaining conductance of the exhaust passage, as enlarging the cold panel to enhance pumping speed reduces the cross-sectional area and thus conductance, particularly in thin designs like baffle or perforated plates.
Innovation Solution
The implementation of a cold trap with a cold panel base and an expansion panel outside the cold panel chamber, where the expansion panel extends into the vacuum chamber, increasing the surface area without obstructing the exhaust passage, thus enhancing pumping speed without decreasing conductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the area of the cold panel is increased to increase the pumping speed of the cold trap, then the pumping speed of the cold trap is improved, but the cross-sectional area of the exhaust passage is decreased, resulting in decreased conductance of the exhaust passage
Solution Approach 1:
The cold panel is configured to extend in the axial direction of the exhaust passage rather than only radially, utilizing the third dimension (length along the passage) to increase surface area. This allows the cold panel to have a large pumping speed while maintaining adequate cross-sectional area for conductance, as the extended cold panel creates a elongated structure that does not proportionally block the passage width.
2Device complexity
If a thin cold trap with a planar cold panel is used, then the device complexity is reduced, but the conductance of the exhaust passage is significantly decreased
Solution Approach 1:
The cold trap is divided into multiple sections along the axial direction, with the cold panel segmented into multiple segments spaced apart from each other. This segmentation allows the exhaust passage to remain open between segments, maintaining conductance, while the cumulative surface area of all segments provides sufficient pumping speed. The structure remains relatively simple compared to complex multi-component designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for increased pumping speed of the cold trap while maintaining high conductance of the exhaust passage, thereby optimizing the performance of the vacuum pumping system without affecting the downstream vacuum pump's efficiency.
Implementation Method 1
A cold panel is placed in an exhaust passage connecting an exhaust port of the vacuum chamber and an intake port of the vacuum pump. The vacuum pump may be a turbo molecular pump. When the in-line type cold trap is used in combination with the turbo molecular pump, the cold trap is primarily used to pump water vapor.
Implementation Method 2
The cold trap includes a cold panel and a cold panel chamber that surrounds the cold panel
Data Source
AI summary
A cold trap is provided between a vacuum chamber and a vacuum pump. The cold trap includes a cold panel and a cold panel chamber that surrounds the cold panel in an exhaust passage. The cold panel includes an expansion panel outside the cold panel chamber. The expansion panel is located in the vacuum chamber.